FilterLab User's Guide - Microchip Technology

1 2003 Microchip Technology s GuideMDS51419A-page ii 2003 Microchip Technology received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 and Mountain View, California in March 2002. The Company s quality system processes and procedures are QS-9000 compliant for its PICmicro 8-bit MCUs, KEELOQ code hopping devices, Serial EEPROMs, microperipherals, non-volatile memory and analog products. In addition, Microchip s quality system for the design and manufacture of development systems is ISO 9001 the following details of the code protection feature on Microchip devices: Microchip products meet the specification contained in their particular Microchip Data Sheet.

2 Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip 's Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code.

3 Code protection does not mean that we are guaranteeing the product as unbreakable. Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of ourproducts. Attempts to break Microchip s code protection feature may be a violation of the Digital Millennium Copyright Act. If such actsallow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that contained in this publication regarding deviceapplications and the like is intended through suggestion onlyand may be superseded by updates. It is your responsibility toensure that your application meets with your representation or warranty is given and no liability isassumed by Microchip Technology Incorporated with respectto the accuracy or use of such information, or infringement ofpatents or other intellectual property rights arising from suchuse or otherwise.

4 Use of Microchip s products as criticalcomponents in life support systems is not authorized exceptwith express written approval by Microchip . No licenses areconveyed, implicitly or otherwise, under any intellectualproperty Microchip name and logo, the Microchip logo, Accuron,dsPIC, KEELOQ, MPLAB, PIC, PICmicro, PICSTART, PRO MATE and PowerSmart are registered trademarks ofMicrochip Technology Incorporated in the and , FilterLab , microID, MXDEV, MXLAB, PICMASTER,SEEVAL and The Embedded Control Solutions Company areregistered trademarks of Microchip Technology Incorporatedin the Maestro, dsPICDEM, , ECAN,ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort,Migratable Memory, MPASM.

5 MPLIB, MPLINK, MPSIM,PICkit, PICDEM, , PowerCal, PowerInfo,PowerMate, PowerTool, rfLAB, rfPIC, Select Mode,SmartSensor, SmartShunt, SmartTel and Total Endurance aretrademarks of Microchip Technology Incorporated in and other Quick Turn Programming (SQTP) is a service markof Microchip Technology Incorporated in the other trademarks mentioned herein are property of theirrespective companies. 2003, Microchip Technology Incorporated, Printed in , All Rights Reserved. Printed on recycled paper. 2003 Microchip Technology iiiMFilterLab s GuideTa b l e o f C o n t e n t sGeneral InformationIntroduction.

6 1 About This Guide .. 2 The Microchip Internet Web Site .. 2 Customer Support .. 3 Chapter 1. Dialog Dialog Boxes .. 5 Chapter 2. Anti-Aliasing Wizard .. Filter Selection Wizard .. 25 Chapter 3. Buttons .. Approximation Combo Box .. Frequency Textboxes .. 39 Chapter 4. File .. Edit .. View .. Filter .. Window .. Help .. 47 FilterLab User s GuideDS51419A-page iv 2003 Microchip Technology 5. Window Frequency View .. Circuit View .. Spice Listing View ..51 Appendix A. FilterLab to SPICE Interface Introduction And 53 Appendix B. Filter Magnitude 57 Appendix C. Group 63 Appendix D.

7 Bessel Filter 65 Appendix E. Op Amp 67 Appendix F. Selected 71 Worldwide Sales and Service .. 72 2003 Microchip Technology 1 MFilterLab s GuideGeneral InformationINTRODUCTIONF ilterLab is an innovative software tool that simplifies active filter design. Available at no cost from Microchip s web site ( ), the FilterLab active filter software design tool provides full schematic diagrams of the filter circuit with recommended component values and displays the frequency allows the design of low-pass filters up to an 8th order filter with Cheby-chev, Bessel or Butterworth responses from frequencies of Hz to 1 MHz. FilterLab also can be used to design band-pass and high-pass filters with Chebychev and Butterworth responses.

8 The circuit topologies supported by FilterLab are the Sallen Key and Multiple Feedback (MFB). The low-pass filters can use either the Sallen Key or MFB, the band-pass is available with the MFB and the high-pass uses the Sallen can select a flat pass band or sharp transition from pass band to stopand. Options (such as minimum ripple factor, sharp transition and linear phase delay) are available. Once the filter response has been identified, FilterLab generates the fre-quency response and the circuit. For maximum design flexibility, changes in capacitor values can be implemented to fit the demands of the application. FilterLab will recalculate all values to meet the desired response, allowing real-world values to be substituted or changed as part of the design also generates a SPICE model of the designed filter.

9 Extraction of this model will allow time domain analysis in SPICE simulations, streamlining the design consideration is given to designs used in conjuction with an Analog-to-Digital Converter (ADC). A suggested filter can be generated by simply inputting the bit resolution and sample rate via the Anti-Aliasing Wizard. This eliminates erroneous signals folded back into the digital data due to the aliasing effect. This section also covers the following topics: About This Guide The Microchip Internet Web Site Customer SupportFilterLab User s GuideDS51419A-page 2 2003 Microchip Technology THIS GUIDED ocument LayoutThe User s Guide layout is as follows: General Information this section describes how to use the FilterLab User s Guide .

10 Chapter 1: Dialog Boxes this section describes the dialog boxes and their uses. Chapter 2: Wizards this section describes the Filter Selection Wizard and helps you design a filter. Chapter 3: Toolbars this section describes the toolbars and their functions. Chapter 4: Menus this section describes the menus and their functions. Chapter 5: Window Views this section describes the window views and how they are used. Worldwide Sales and Service this section gives the address, telephone and fax number for Microchip Technology Inc. sales and service locations throughout the Microchip INTERNET WEB SITEM icrochip provides on-line support on the Microchip World Wide Web (WWW) web site is used by Microchip as a means to make files and information easily accessible to customers.